Background Caryopteris mongholica Bunge is a rare broad-leaved shrub distributed in the desert and arid regions of Mongol and North China. Due to land reclamation, natural habitat deterioration and anthropogenic activities in recent years, the wild resources have sharply reduced. To effectively protect and rationally use it, we investigated the genetic diversity and population structure from 18 populations across the range of C. mongholica in China by reduced representation sequencing technology. Results We found the overall average values of observed heterozygosity (Ho), expected heterozygosity (He), and average nucleotide diversity (π) were 0.43, 0.35 and 0.135, respectively. Furthermore, the NM17 population exhibited higher genetic diversity than other populations. The phylogenetic tree, principal component analysis (PCA) and structure analysis showed the sampled individuals clustered into two main groups. The NM03 population, with individuals clustered in both groups, may be a transitional population located between the two groups. In addition, most genetic variation existed within populations (90.97%) compared to that among the populations (9.03%). Interestingly, geographic and environmental distances were almost equally important to the observed genetic differences. Redundancy analysis (RDA) identified optical radiation (OR), minimum temperature (MIT) and mean annual precipitation (MAP) related variables as the most important environment factors influencing genetic variation, and the importance of MIT was also confirmed in the latent factor mixed models (LFMM). Conclusions The results of this study facilitate research on the genetic diversity of C. mongholica. These genetic features provided vital information for conserving and sustainably developing the C. mongholica genetic resources.

AimsThe genetic variation caused by long-term adaptation to the environment has significant influence on plant's growth and development. Leaves serve as the most important and sensitive organs to environmental changes. Understanding the adaptive variation of leaf anatomical structure in different environments is the basis for exploring the adaptation of plants to the environment. Methods Common garden experiment is an effective method to study the effects of genetic and environmental factors on plant growth and metabolism. In this study, the influence of environmental gradients was eliminated by using the common garden experiment. Then we analyzed anatomical structures of leaves and its driving factors of Caryopteris mongholica from seven different provenances by using conventional paraffin section, multiple comparisons, correlation analysis, and general linear model analysis method.Important findings Caryopteris mongholica from seven provenances had typical isolateral leaves, with no differentiation of spongy tissue, and the upper epidermal cell was thicker than the lower epidermal cell. Meanwhile, the upper palisade tissue was thicker than the lower palisade tissue. There was a significant autocorrelation among anatomical parameters of leaves, and there were important differences among the anatomical structures of leaves from different provenances. With increasing mean annual temperature of provenances, the thickness of the leaves and palisade also showed an increasing trend, and the largest thickness of the upper palisade tissues, lower palisade tissues and leaf thickness were in the leaves of Alxa Left Banner, Nei Mongol, indicating a stronger

Caryopteris mongholica is a rare resource plant distributed in typical steppe, desertified steppe and desert areas. Based on field survey data sampled during the growing seasons from 2018 to 2021, combined with relevant previous literature, this study analyzed the distribution and environmental characteristics of C. mongholica population, the characteristics, classification and species diversity of C. mongholica community, and the influence of environmental factors. The results showed that: (1)The C. mongholic population was mainly distributed in the east, middle and west of Inner Mongolia Autonomous Region, the north of Loess Plateau, Hexi corridorm, Qilian Mountains and other northwest temperate desert or steppe areas in China. It was the dominant species or companion species in the community. (2) According to the survey of 40 sample plots, a total of 141 species of seed plants were recorded, belonging to 110 genera of 37 families, and families of Compositae, Leguminosae and Gramineae played crucial roles in the species composition. Among them, 42 of these species were shrubs and dwarf/semi-shrubs, 76 were perennial herbs, 23 were annuals and biennials. In the class of species presence, 88.02% were occasional species with frequency distribution smaller than 20%. Typical xerophytes occupied the main advantage(32.39%) in the water ecological types. East Palearctic elements(25.35%) were the major floristic geographic elements. (3) Based on the life form and dominance of species, the C. mongholica communities were divided into 6 major association groups,which were further divided into 23 associations. (4)Precipitation, solar radiation and other environmental factors significantly affect the distribution of C. mongholica population and the species diversity of the community. Key word: Caryopteris mongholica, population distribution, community characteristic, species diversity

Background Quantifying intra-specific variation in leaf functional traits along environmental gradients is important for understanding species' responses to climate change. In this study, we assessed the degree of among and within populations variation in leaf functional traits and explored leaf response to geographic and climate change using Caryopteris mongholica as material, which has a wide range of distribution environments. Results We selected 40 natural populations of C. mongholica, measured 8 leaf functional traits, analyzed the extent of trait variation among and within populations, and developed geographic and climatic models to explain trait variation between populations. Our results showed that the variation in leaf functional traits of C. mongholica was primarily lower within populations compared to among populations. Specifically, the leaf area (LA) exhibited higher variability both among and within populations, whereas leaf carbon content (LC) exhibited lower variation within populations but greater variation among populations. We observed a specific covariation pattern among traits and a strong linkage between morphological, economic, and mechanical traits. Increasing minimum temperature, precipitation of month, and seasonal precipitation differences all limited the growth and development of C. mongholica. However, it was observed that an increase in mean annual precipitation positively influenced the morphological development of its leaf. Conclusions These results demonstrate the response of intra-specific trait variation to the environment and provide valuable insights into the adaptation of intra-specific leaf functional traits under changing climatic conditions.